Description: (Taken directly from the application) Shock wave lithotripsy (SWL) is now used to manage almost 85% of all urinary stone patients. Despite its widespread application, no specific guidelines exist for the exposure of renal tissues to high-intensity shock waves. Basic and clinical studies have clearly demonstrated that shock wave lithotripsy can induce acute and long-term bioeffects at both cellular and tissue levels, and cavitation (the formation, and subsequent expansion and collapse of pressure wave-induced microbubbles)has been identified as the dominant mechanism for tissue injury, as well as for stone comminution. However, all existing clinical lithotripters are not equipped with any means to monitor the exposure of patients to cavitation, and the treatment procedure is substantially empirical. Therefore it is important and clinically relevant to develop a non-invasive technique to determine activity in situ, and to use such an technique to guide the effective and safe application of high-intensity shock waves in patients during shock wave lithotripsy. We propose to use simultaneous high-speed photography and acoustic emission measurements to characterize the acoustic cavitation induced by shock wave lithotripters. The overall strategy is first to characterize quantitatively the transient acoustic cavitation generated in vitro using different lithotripter systems. Then, this information and the measurement techniques developed thereof will be used to define the cavitation threshold in vivo, and to establish the correlation between cavitation and resultant stone comminution and concomitant tissue injury. An improved theoretical model of bubble dynamics is constrained media will be developed to facilitate the interpretation of acoustic emission signals from in vivo measurements. Furthermore, lipid peroxidation and its associated cellular byproducts will be analyzed using a microdialysis technique, both in blood and urine. These studies shall allow us to better understand both the physical and biological mechanisms of tissue injury, and to develop non-invasive markers for assessing cavitation in vivo during shock wave lithotripsy.